Collapsible bit



P.`B. MITCHELL "COLLAPSIBLE BIT. PPucAIloN FILED MAY 1 6. 1921.

1,435,491.; Patented Nov. 14,1922.

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16 .15 .16' v @gm l ation/WRF n P. B. MITCHELL COLLAPSIBLE BIT. APPLlc/mou man MAY|6,1921.

1}435,491'. Patented Nov. 14,1922.

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Patented Nov. 14, 1922.

unirte i smits maar i PATE N T1] Q F F! PRESSE B. MITCHELL, 0E HOMEIL LOUISIANA.

e CoLLArsIBLE EIT.

Application mee Mayis, 192i. seria; No. 469,993;`

To all whom it 'may concern:

Be it known that I, PRESSE B. MITCHELL,"

an improved means for permittinga drill bit to be withdrawn for resharpening or the like, without necessitating the withdrawal of the drill stem from the hole, thereby resulting in the saving of time and labor.l

Another object of the invention is 4the provision of a rnovel collapsible drill bit, a

novel drill stem for receiving the bit, and aj novel means of associating the bit with the stern in order to hold the bit firmly in its operative position during drilling. i

A further object of the invention is to provide a novel carrier forlthe'collapsible bit, which embodies means for collapsing the bit in order to permit the withdrawal theref, of from the stem, and means lfor normally urging the bit into an operative position when the bit reaches its lowermost drilling position in relation to its stem. c I

A still further object of the invention is to provide an improved collapsible drill bit apparatus of the above character, whichwill be durable and eflicient in use, one thatwill be simple and easy to manufacture, and one which can be placed upon the market at a reasonable cost.

With these and other objects in View, the invention consists in the novel construction, arrangement and formation of4 parts, as will be hereinafter more specifically described,

claimed and illustrated in the accompanyino' drawings, forming a part of this speci-L D l l c cation, 1n which drawings:

Figure l is a vertical longitudinal section through the improved drilling apparatus.` Figure 2 is a. similar view showing the y bit in its collapsedl position ready for withdrawal from the stem. v e

Figure 3 is a verticallongitudinal section through the drilling apparatus taken at right angles to Figures 1 and 2.

Figure 4 is a fragmentary side elevation of the drilling apparatus showing a portion of the drill stem in section. y Figure 5 is a top planview of .theimvfishA tailed bit now vin vogue.

vFigure' 6 is a bottom planview thereof,

showing" the vbit blades in their extended positions. y l Figure T is a detail' horizontal section' taken on the line 7 7 of Figure 2.

Referring to the drawings "in detail,

Several views, the letter A indicates thefdrill wherein similar reference characters desig nate corresponding `.parts throughout the stemyB, the bit; andCpthe carrier for thebit. y, I l, 1 r,` The .drill stem A includes thel usual l pliijrality Aofpipe sections, and the lowermost section has been designated b-y the numeral 104 and will be hereinafter referred to. as the drill holderandwill now be specificallyde-` scribed.

The tool holder 1Y0. includes ythe elongated 75 y cylindrical body, which has 'its `upper end threaded for receiving the lower end ofthe adjacent pipe section,y and the inner surface' has its lower end flared lor grooved at' dia-Iv metrically opposite points asf at 11, for receiving the bit B as will be hereinaftermore fully described.`v The lower end of the holder 10 on each side of the flared'y portion', vllfis provided with s top shoulders `12wliich 'de-` finel therebetween a guide 13,. forthebit B,

The shoulders 12. form stops for the bit car-.

rier C.v The laredportions 1 1 ofthe tool holder C 'are provided adjacent toftheiij.

lower ends with stop shoulders 14, thep'urpose of which will also be described.

Thefbit B includes a pair of blades 15, and these'blades,iwhen intheir extended opera-` tive positions' appear similar to Each fof the blades 15 include alongitudinally extended body having itsouter edge provided witha-y notch vor 'shoulder V15 for, engagingthe shoulders lll formed in the flared guide way 11.`v` The outer 'edges of the blades 15: are sharpened,- as `at 16, to provide Icutting edges, similar to 'the ordinary fish tail gbit .These blades 15V adjacent to their upper in-l ner edges are provided with oppositely eX- tending slots 17 which eXtendat an angle to the longitudinal center of the bladen, f The carrier C forthe Vbitincludes upper and lowerelliptical shaped heads 18 "an d .19

the ordinary f which are'connectedftogether by a cylindri-` cal .shank 201r The .lower head 19 isprovided withaninwardly'extending slot orre-r vcess 20', inwhich areadapted to fit the upper endsA 'ofthe bit blades 15,. This head carries a diametrically extending pivot'pin iassnei 21, which extends through the upper ends of the blades and holds the same in position onthe carrier. The opposite side walls of the slot or recess 20 adjacent to their lower ends are flared as at 22, to permit the blades` to swing on the pivot pin 21. The head 19 is also provided with the slot 23 opening out through the side walls of the head and communicating with the slot or recess 20', and these slots 23 slid-ably receive a .cross pin 24, which is mounted in the slots 17 formed in the blades 15. rlhis cross pin 24 has its terminals secured to suitable Iguidi-5 strips 25, which are slidably mounted inr and thus be moved to their operative or in' operative positions. The movement of the bladesy is accomplished by the pin 24 riding in the inclined slots 17.

` 18 and the` connecting shank 20 are provided witha longitudinally7 extending bore, which slidably supports the operating rodv 29. The kupper end of this rod 29 may be pro` vided with a suitable head 30, in ordery that the same may be readily engaged by a grap-` `lower convolution of which engages the strips 25, while its upper convolution rests against a shoulder 88 formed by the reduced portion 31 of the shank. The spring normally tends to force the strips downwardly in the guides 26, and consequently swings the bit blades 15 on the pivot pin 21 to their normal operative position `through the' medium of the pin 24 and the slots 17. The inner surface of the holder 10 at diametrically opposite points is provided with a pair of longitudinally extending ribs 34, which communicate with thenshoulders 12 at their lower ends.- These ribs 34 are so disposed in relation to the elliptical heads 18 and 19 as not to interfere withthe movement thereof during the raising and lowering of the bit B. These ribs 84 vare provided with longitudinally extending passageways 85. These passageways 35 also extend through the shoulders 1 2 and open out at the lower end of the bit holder 10.v The upper ends of these passageways 35 terminate in laterally extending passageways 36, which openr into the interior of the holder 10 below the upper endsl of the ribs 34. These passageways form means forpermitting waterforthe like The. upper headv to be forced against or adjacent to the cutting edges of the blades 15, in order to remove or wash all debris from around the same.

ln operation ofthe improved device, when it is desired tolower a bit in position, the carrier C is lowered into the drill stein by means of the actuating rod 29. inasmuch as the actuating rod 29 is then supporting the weight of the carrier @the pin 24 will. be in itsraised position at the upper ends of the slots 17, consequently holding the bit blades 15 in their folded position, as shown in F ure 2. lVhen the carrier C reaches its' lowermost position, the same will seat von v the shoulders 12,v thus releasing the weight ofv vthe carrier from the rod 29 and the s3rin T 7 2D 32 engaging the upper ends of the stripsA 25, will force the pin 24 downwardly lin the slots 17 to the lower ends thereof, thus spreading the'bit blades 15 and forcing the same to their operative positions. This will move the shoulders 15 formed on the blades 15 into engagement with the shoulders 1.4y torined in the passageways 11.` rlhiseliminates any movement of the blades into the holder during the drilling process. It also can be seen that owing to the shape ofthe heads 18 and 19, relative rotation between they carrier C, the bit B and. the holder 19 will be absolutely precluded. When it is desired to raise the bit B,-for any cause w.hat-. sover, it is merely necessary to lower agrapple into the stem into engagement withtlie head 80 and start to raise the carrier. rihe rod 29 will be irst raised in the carrier for moving the pin 24 to the upper ends of the slots 17, which will move the bit blades 15 to their folded position, and the shoulders 15 out of engagement with the stop shoulders 14. Upon further upward movement of the rod 29, the carrier C and the bit B; will be raised.

lf so desired the bit B can be readily kdisconnected from the carrier simply by removing the pins 24 and 21, which are merely slipped into positionv These pins are prevented from accidentaly displacement, when the carrier C isin its` lower position by their engagement with the holder A, and the strips 25. ,c

From the foregoing description, it can be seen that an exceptionally simple and durable drilling apparatus has beenV provided, in which a novel collapsible bit can be ready ily placed in or removed from position without necessitating the pullingl of theentire drill stem.

Changesin details may be made without departing from the spirit or scope of this invention; but, Y

l claim: y

1. In a drill apparatus, a Abit holdery including a cylindrical body, spaced shoulders forme-d in the body adjacent to its lower end tween, a bit carrier slidably mounted in the voody, a bit including a pair of pivoted blades, means pivotally securing the blades to the carrier, shoulders formed on the outer longitudinal edges of the blades, and shouldersv formed on the side walls of the `guide way arranged to engage the shoulders formed on the bit blades when the same are in their extended operative positions.

3. In a drill'apparatus, a bit holder including a cylindrical body, spaced shoulders formed in the body adjacent toitslower end defining a guide way therebetween, the side `walls of the guide way having shoulders formed therein, a bit carrier slidably mountf ed in the body arranged to seat upon the first mentioned shoulders when the same `is in its lowermost position in the body, a pair of bit blades pivotally secured to the carrierand arranged to extend in the guide way,

' shoulders formed on the outer longitudinal edges of the bitl blades arranged to engage the second mentioned shoulders, when the blades are in their 'extended operative positions, an operating rod slidably carried by the carrier, and means operatively connecting the rod with the blades to permit the blades to be moved to their extended or folded positions. l

4. In a drill apparatus, abit holder including a cylindrical body, a bit carrier slidably mounted in the body, a bit connected to the carrier including a pair of pivoted blades, an actuating rod s lidably mounted in the bit carrier, the bit blades having a pair of diagonal slots formed therein lbelow the pivot point thereof, and a pin slidably mounted in said slots and connected to said actuating rod, whereby .upon movement of the rod, the blades will be moved to their extended or folded positions.

5. In a drill apparatus, a bit carriervincluding a cylindrical body, a bit carrier slidably mounted in the body, a bit including a pair of blades', means pivotally securing the blades at their upper ends to the lower end of the bit carrier, the bit blades having a pair of diagonally extending slots formed therein below the pivot .points thereof, a cross pin slidably mounted in the slots, an actuating rod slidably mounted in the carrier, means operatively connecting the cross pin with the rod, and spring means normally urging the cross pinv toward the lower ends of said slots, whereby the Abit blades will be normally' held in an extended position.

6. In a drilling apparatus', a bitcarrier including a body having a lower slotted end, a bit including a pair of blades havin their upper ends' inserted in the sloltte portion of the body, a pivot pin extending through the body and the upper ends l of the blades, the blades having oppositely directed diagonal slots formed therein, an

operating rod slidably mounted in the carrier, a cross pinslidably carried by the .bodyand mounted in said slots', means connecting the crosspin with the actuating rod, and a so j spring coiled around the .carrier and nor mally holding the cross pin in the lower ends of theslots lformed in the blades.

7.`Ina drilling apparatus', a bit carrier having a lower slotted end, a bit including a pair of blades mounted in the `slotted end of the carrier, a pivot pin extending through the body and blades, the blades having a pair ,of oppositely extending diagonal slots formed therein, the opposite sides of the oarrierybeing provided with guide grooves, strips slidably mounted in the guide grooves, ya pin carried by the lower ends of the strips and slidably mounted in the carrier and in the slots formed in the blades, a longitudinally extending" axially disposed operating rod mounted in the body, a second cross pin carried by the rod, theupper ends of the strips being connected to the second cross pin, and anV expansion spring coiled around the carrier and engagingy thev upper ends of the strips to vnornrially urge the same and the first mentioned cross pin downwardlyin relation to the carrier andblades. 8. In a drill apparatus, a drill holder, a

drill bit carrierv slidably mounted in they holder including a pair of elliptical shaped heads, and a connecting shank, the holder v having oppositely disposed longitudinally extending ribs formed therein, water channels formed in thel ribs, opening out into the upper end of the holder and out through the lower end of the holder, and a drill bit-v yincluding a pair of blades secured to the carrier.

nected to the shoulders, the ribs and shoul-V ders havinglfluid channels formedv therein opening out through the lower end of the body and into the body at the upper end thereof.

PRESSE B. MITCHELL. l

iio

, 115` 9. In a drilling apparatus, a drill holder y including a tubular body, a pair of shoulders formed on the inner surface of the lbodyf 

